water changes

Hiya you lot! Hope you dont mind me asking a dumb question but I have been reading on different places about water changes and just want to make sure I am doing things right.

I change about 1/3 of water every week but have read that some people think its rght to change 50-60% every week or two. Which is the best way to do it - I dont want to have the fish swimming round in unsafe or stale water. Also I have quite a few ornaments in the tank. I dont vac under them every week but did over the weekend and there was tons of muck under it, much more than in the normal gravel really dirty!

How often should I move them and clean under because I dont know if that removes all the bacteria that is needed for the filter or if it is just muck and I should be more careful about it.

Thanks

30-40% weekly is definitely better than a fortnightly change. A lot of water chemistry changes can occur in a week. Also, the best description I read was, that for the fish, the new water is the equivalent of opening a window to let in a breath of fresh air. I find they're definitely more energized afterwards.

There's no real need to clean under the decor too often as a certain amount of bacteria will inhabit the gravel but it's personal choice really. If you feel like doing it and the decor is easily accessible, do - if not, don't!

Another good reason to get live plants though, they'll absorb any decomposing food/faeces in the substrate. I only gravel clean the bare bits of substrate which, as the plants spread, is getting less and less. I know some people who never gravel clean heavily planted tanks but I'm not sure I'd go that far.